Lid for accumulator batteries and charging devices co-operating with said lid

ABSTRACT

A lid for accumulator batteries has one or more holes to receive a device to ensure the circulation of electrolyte during the first charge and a second device to ensure the re-fill of electrolyte during the other charges. The lid is equipped with one or more channels each having one end facing the surface of the one or more holes and the opposite end coupled with at least one duct on the inner vertical wall of the container.

BACKGROUND OF THE INVENTION

The invention concerns a lid for electric accumulator batteries which issuited to obtain quick charges and devices co-operating with said lid,suited to obtain said quick charges.

It is a known fact that the electric accumulator batteries undergo aseries of charges during their lifespan which are done by connectingtheir poles with an external source of electric power.

In particular, when the accumulator batteries are new, they undergo afirst charge which is done by the manufacturer and which is needed forthe formation of the elements. Successively, during their lifespan, theyalso undergo a plurality of other charges which are done by the user,each of them being suited to restore their best operating conditions.

It is a known fact that the charging process is rather long (8 to 10hours approx.) but it can be considerably shortened by performing thecharge with suitable expedients. For instance, it is a known fact thatthe time to perform the first charge for the formation of the elementscan be considerably shortened, if the charge itself is done by usingelectrolyte at low density kept at a constant temperature by means of anexternal recycling process in a cooling closed circuit.

With regard to the successive charges which are performed during thelifespan of the accumulator battery, these can also be accelerated ifwhile they are performed, air under pressure is let into the accumulatorbattery, since air under pressure, by causing the electrolyte to bubble,prevents its stratification.

By operating with such expedients, the charging and recharging times areconsiderably shortened.

SUMMARY OF THE INVENTION

There are some known devices which are applied to the accumulatorbatteries and which perform the recycling of the electrolyte and itssimultaneous cooling inside the accumulator battery, thus allowing theuser to quickly perform the first charge for the formation of theelements. Such devices belonging to the known technique present,however, the inconvenience that the inlet of the electrolyte occursthrough the upper part of the container and, consequently, the recyclingprocess mostly affects the upper layers of the electrolyte rather thanthe layers in the middle position or near the bottom.

With regard to the maintenance re-charges of the accumulator batterywhich are performed by the user during the lifespan in the accumulatorbattery itself, there are some known devices which permit the blowing ofair inside the accumulator battery during the re-charging operation,thus preventing the stratification of the electrolyte. Such devicesbelonging to the known technique essentially consist of a vertical tubewhich penetrates into the accumulator battery until it is near thebottom and through which air is blown in by means of a terminal sleeveattached to the lid.

One limit that such devices present is that they only allow the blowingof air but they do not also allow the re-filling of the electrolytewhich is always necessary during the re-charging operations. It isunderstood that such an operating method implies rather long performingtimes.

The purpose of the present invention is to the overcome the mentionedinconveniences.

The first purpose of the present invention is to obtain a lid foraccumulator batteries to which it is possible to apply a first devicewhich permits the cooling and the closed-circuit circulation of theelectrolyte outside the accumulator battery that affect the whole massof the electrolyte itself, so as to quickly perform the first charge forthe formation of the elements.

Another purpose of the present invention is to obtain a lid foraccumulator batteries to which it is possible to apply a second devicewhich permits the blowing of air into the accumulator battery, so as toquickly perform also the maintenance re-charges during the lifespan ofthe accumulator battery.

Another purpose is that said second device also permits the re-fillingof the electrolyte.

Not the last purpose is that the lid according to the invention and thedevices applicable to it and suited to perform such quick charges, alsopermit the discharge of the fumes which develop during the chargesthemselves and their conveyance to the outside.

The described purposes are achieved by a lid for accumulator batterieswhich, in accordance with the main claim presents, on its essentiallyflat surface, one or more holes each suited to receive a first device toensure the circulation of the electrolyte during the first quick chargefor the formation of the elements and a second device to ensure there-fill of the electrolyte and the other quick charges during thelifespan of the accumulator battery and is characterized in that it isequipped with one or more channels made in said surface, each of thempresenting one end facing the cylindrical surface of said one or moreholes and the opposite end coupling with a duct present on the innervertical wall of the container of the accumulator battery which said lidmatches, said duct ending near the bottom of said container.

Said first device is characterized in that it comprises a body having asuitable shape so as to be inserted into one of said one or more holesof said lid, said body presenting:

a first way to let the electrolyte into the accumulator battery, saidfirst way presenting one end connected with a pipe for the inlet of saidelectrolyte and its opposite end communicating with an annular recessmade in the body of said first device and communicating with thecorresponding end of each one of said first channels;

a second way to let the electrolyte flow out of the accumulator battery,said second way presenting one end connected with a pipe for thedischarge of said electrolyte liquid and its opposite end protrudinginside said container and suited to maintain by overflow the level ofelectrolyte inside the accumulator battery.

DESCRIPTION OF THE INVENTION

Said second device comprises:

a body which can sealingly be coupled within one of said one or moreholes of said lid of an electric accumulator battery and which presentsa cavity provided with a bottom, said body presenting one or more firstducts for exhausting the fumes and one or more second ducts for theinlet of the re-fill liquid;

a tubular element which presents an outer tubular part which coupleswithin said cavity of said body and a cylindrical guiding elementinnerly co-axial within said outer tubular part, said tubular elementbeing provided, in its interior and in its middle positions, with atransversal surface equipped with a through hole and, laterally on thecylindrical wall, with one or more through openings communicating withat least one of said one or more second ducts belonging to said body;

a tubular stick slidingly coupled within said through hole of saidtransversal surface and presenting, at one end, a floating bodyco-operating with the liquid contained in the accumulator battery and,at the opposite end, a flexible membrane connected with said tubularstick through first sealingly locking means and connected with the innerlateral surface of said tubular element through second sealingly lockingmeans, said tubular stick being provided, in its essentially middleposition, with closing means suited to sealingly co-operate with saidhole of said transversal surface, so as to allow or to prevent thepassage of the re-fill liquid coming from said one or more second ducts,said flexible membrane defining a discharge chamber inside one side ofsaid cavity of said body, which communicates with said one or more firstducts and with the end of said tubular stick and, on the opposite side,a build-up chamber for the collection of the re-fill liquid whichcommunicates with said one or more second ducts and within which, thepressure of said liquid contained in it, causes the deformation of saidmembrane, thus producing on said tubular stick a force such as toincrease the pressure exerted on said closing means by said floatingbody, and is characterized in that said build-up chamber communicateswith a duct equipped with a capillary section joining an annular recesspresent on the outer surface of said body, said annular recess defining,together with the wall of the hole lodging said device, an annularchamber which communicates with said tubular channel of said lid, saidcapillary section preventing the passage of electrolyte from thebuild-up chamber to said channel but permitting the passage ofcompressed air which is let into said second inlet duct of said deviceduring the re-charging process of the accumulator battery.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specific example,while indicating a preferred embodiment of the invention, are given byway of illustration only, since various changes and modifications withinthe spirit and scope of the invention will become apparent to thoseskilled in the art from this detailed description and from the drawings,wherein:

FIG. 1 shows in an axonometric representation the lid according to theinvention;

FIG. 2 shows the lid of FIG. 1 applied to the container of anaccumulator battery and equipped with the first device suited to ensurethe circulation of electrolyte during the first quick charge for theformation of the elements;

FIG. 3 shows in an external front view the first device according to theinvention;

FIG. 4 shows in an axonometric representation the first device accordingto the invention of FIG. 3;

FIG. 5 shows the lid according to the invention and the first devicematching it which ensures the inlet and the recycling of electrolyte;

FIG. 6 shows the two accumulator batteries equipped with the lidaccording to the invention and with their corresponding first device toensure the circulation of electrolyte, both said first devices beingconnected with the external recycling and cooling circuit;

FIG. 7 shows in a cross-section the second device according to theinvention suited to be applied on the lid, also being the object of thepresent invention, in order to allow the subsequent re-charging andre-filling operations;

FIG. 8 shows an external view of said second device represented in FIG.7;

FIG. 9 shows the second device represented in FIG. 7 during there-filling phase of electrolyte;

FIG. 10 shows the second device represented in FIG. 7 once there-filling phase has been completed.

The lid for accumulator batteries, object of the present invention, isrepresented in FIG. 1 wherein it is indicated as a whole with 1 andwherein it can be observed that it comprises an essentially flat surface2, on which there are a pair of holes 3 and 4 suited to permit theinsertion of the poles and another through hole 10 suited to receive thedevices for the quick charge, object of the present invention, and whichwill be described hereinafter.

In particular, on the surface 2 of said lid 1 it can be observed thatthere is a channel 5 which presents one end 51 facing the cylindricalsurface of said hole 10 and the opposite end 52 coupling with a duct 62which, as can be observed in FIG. 2, is present on the inner verticalwall of the container 6 of the accumulator battery to which said lid 1is coupled and which stretches along said inner vertical wall endingnear the bottom 71.

It is pointed out that in the Figures and in the descriptions followinghereinafter, reference is made to a lid 1 provided with a single throughhole 10 suited to receive the device according to the invention and witha single channel 5 to set into communication said hole 10 with theinterior of the container 6 of the accumulator battery. Such adescription, restricted to a single hole and a single channel, is givenby way of illustration only since in different embodiments the lid ofthe accumulator can be provided with any number of through holes 10 andwith any number of channels 5 and, consequently, with a correspondingnumber of ducts 62.

As can be observed in FIG. 2 and in better detail also in FIG. 5, afirst device, indicated as a whole with 20, also visible in the drawingrepresentations of FIG. 3 and FIG. 4, is applied to the lid 1. Saiddevice permits to ensure the circulation of electrolyte during the firstquick charge for the formation of the elements of the accumulatorbattery, which is performed by the manufacturer.

In fact, it has been said that in order to obtain the first charge ofthe accumulator battery for the formation of the elements in a quickway, the known technique foresees the connection of the poles of theaccumulator battery to an external source of electric power, whileperforming at the same time, a recycling process of electrolyte inside aclosed circuit, equipped with a cooling system suited to keep constantthe temperatures of electrolyte during the charging process. In order toaccelerate such a charging process, it is also necessary to useelectrolyte with a low concentration which is let into the accumulatorbattery until it reaches a level which is lower than the predeterminedfinal level. When the charging process has essentially been completed, acertain amount of highly concentrated electrolyte is added, so as toreach, inside the accumulator battery, both the level of electrolyte andthe concentration which have been predetermined.

For this purpose the process of quick charge is divided into two phasesand, precisely: a first phase when the charge is obtained with therecycling of electrolyte with a low concentration, and a second phasewhen the electrolyte at high concentration is let into the accumulatorbattery. For this reason the first device object of the presentinvention, indicated as whole with 20, is used. The same, as can beobserved in the FIGS. 3, 4 and 5, comprises a body 21, having a suitableshape so as to be sealingly inserted into said hole 10 of said lid 1,which presents a first way 22 for the inlet of electrolyte following thedirection 250 and a second way 23 for the outlet of electrolyte itselffollowing the direction 260, wherein said ways are connected with anexternal circulating system which will be described hereinafter.

It can be observed, in particular, that said first way 22 presents oneend 122 connected with a feeding pipeline 222 represented in FIG. 6 andbelonging to said external recycling unit, indicated as a whole with600, while the opposite end 322 communicates with an annular recess 422,made in the body 21 of said first device 20, which through said channel5 and said vertical duct 62 communicates with the interior of thecontainer 6 of the accumulator battery, near the bottom 71.

With regard to said second way 23, this presents one end 123 connectedwith an overflow pipe 223 which, as can be observed in FIG. 6, belongsto the same circuit 600 for the external circulation of the electrolyteand the opposite end 323 which protrudes inside said container 6. Saidsecond way 23 consists of a tubular element 423 which presents, in itsmiddle position, an annular area having a larger diameter 424, slidinglycoupled inside a chamber 120 belonging to said body 21 of said firstdevice 20. Said annular area having a larger diameter 424 defines,inside said chamber 120, an upper area 220 and a lower area 320separated from one another, each of them presenting an opening 420 and520 respectively, which permits the inlet or outlet of air underpressure in their respective chambers. In order to perform in a quickway the charge for the formation of the elements, the first device 20 iscoupled with the hole 10 of the lid 1, making sure that it seals it bymeans of the interference of the OR rings 225 and 226 belonging to it,against the wall of said hole 10. Through the opening 420 of said firstdevice 20, air under pressure is let in; this acts on the largerdiameter 424 of the tubular element 423 and causes the latter todescend, so that its end 323, as can be observed in FIG. 5, placesitself in the position 500 indicated by the dotted line and defines byoverflow the level 60 of the electrolyte 61. The electrolyte 61 is a lowconcentration electrolyte which, by means of the recycling unit 600 andthrough the pipelines 222, 223 and 610 which connect a plurality offirst elements 20 in parallel with one another, is made to circulate ina closed circuit outside the accumulator battery following the direction620 represented in FIG. 6 and in a closed circuit inside the accumulatorbattery following the direction 510. The recycling unit 600 comprises,in fact, a pump, a cooling unit and a system for exhausting the fumes,indicated as a whole with 630, which permit not only the forcedcirculation of electrolyte, but also its cooling so as to keep it at aconstant temperature.

During the circulation of electrolyte, all the fumes produced areexhausted, since they follow the flow of electrolyte going out throughsaid second way 23, thus permitting to operate in a healthierenvironment.

It is obvious that the circulation of electrolyte can also occurfollowing directions opposite to the directions 620 and 510, the sameresults being achieved.

When the charging process of the accumulator battery is almostcompleted, air is let in through the opening 520 of the chamber 120which, by acting on the annular area having a larger diameter 424,vertically lifts the tubular element 423 and spaces out by a length 523its end 323 from the level 60 of the electrolyte 61.

Through the second way 23, the highly concentrated electrolyte is filledin in such an amount as to determine a new level 560 corresponding tothe overflow level of the end 323, as can be observed in FIG. 5. Saidconcentrated electrolyte which is added, mixes with the lowconcentration electrolyte 61 already present inside the accumulatorbattery, bringing the concentration to the required value, carrying onwith the final charge of the electric accumulator battery.

Said first device 20 is removed from the hole 10 within which it islodged, the hole 10 is closed and the accumulator battery can be sent tothe user.

It has been seen how, by using the lid 1 and said first device 20 whichcan be coupled with it, both object of the present invention, it ispossible to obtain in a quick way the charge for the formation of theelements of the accumulator battery.

During its use the accumulator battery is liable to discharge and,therefore, from time to time, the user has to carry out the normalperiodical maintenance operations which imply re-charging and re-fillingwith the electrolyte.

In order to carry out such operations, a second device, also object ofthe present invention, indicated as a whole with 30 in the FIGS. 7 and 8is applied on lid 1. In FIG. 7 it can be observed that said seconddevice is also coupled with the same hole 10 of lid 1.

It can be observed in particular, that said second device 30 comprises abody 31 which can be sealingly coupled with the same hole 10 of the samelid 1 and is provided with a cavity 11 limited by a bottom 32.

Said body 31 presents laterally one or more first ducts 33 for theexhaust of the fumes, essentially lying on the same plane and one ormore second ducts 34 for the inlet of the re-filling liquid, essentiallyco-planar and lying on a plane placed below the plane on which saidfirst ducts 33 lie and essentially parallel with it.

Said ducts are connected with pipelines, not represented in the Figure,which permit the outlet of the fumes from the accumulator battery andthe inlet of the re-fill liquid in the accumulator battery,respectively.

A tubular element 35 is coupled with the body 31 of said second device30. Said tubular element consists of a tubular outer part 135 which isinserted into said cavity 11 of said body 31 and of a cylindricalguiding element 235 internally co-axial with said tubular outer part135.

A transversal surface 36 equipped with a through hole 37, is internallyand transversally arranged in said tubular element 35 and it rigidlyconnects with each other said cylindrical guiding element 235 with thebody of said tubular element 35.

Moreover, said tubular element 35 presents laterally on its cylindricalwall, one or more through openings 41, each of them communicating withat least one of said one or more second ducts 34 belonging to said body31, whenever said tubular element 35 is coupled with the body 31 of saidsecond device 30.

The device 30 according to the invention also comprises a tubular stick38 which is slidingly inserted into said through hole 37 of saidtransversal surface 36. Said stick 38 presents, at one end, a floatingbody 39 which co-operates with the liquid contained in the accumulatorbattery and, at the opposite end, it presents a flexible membrane 40which is connected with the tubular stick 38 through first sealinglylocking means 140 and, at the same time, it is also connected with theinner lateral surface of said tubular element 35 through secondsealingly locking means 240. Moreover, said tubular stick 38 isequipped, in its essentially middle position, with closing meansconsisting of a shutter 42 in the shape of a truncated cone, suited tointercept the through hole 37 of said transversal surface 36.

In order to guarantee the centering of said tubular stick 38 inside thecylindrical guiding element 235 within which it is inserted, said stickis equipped with guiding fins 435 which are slidingly coupled with theinner surface of said cylindrical guiding element 235.

The flexible membrane 40 locating, inside the cavity 11 of said body 31of said second device 30, on one side, a exhaust chamber 243 whichcommunicates with said one or more first ducts 33 and, on the oppositeside, a build-up chamber 43 which communicates with said one or moreseconds ducts 34. Moreover, said build-up chamber 43 also communicateswith a duct 50 arranged in correspondence with the transversal surface36 and which presents a capillary section 56 joining an annular recess53 present on the outer surface of said body 31. Said annular recess 53defines, with the wall of the hole 10 lodging said second device 30, anannular chamber 54 which communicates with said tubular channel 5 of lid1.

Therefore, in order to perform the periodical maintenance operation,consisting of re-charging and re-filling the accumulator battery, aftercoupling said second device 30 with each of the holes 10 of theaccumulator battery, the re-filling of electrolyte is carried out byintroducing the re-fill liquid through the second ducts 34, as can beobserved in FIG. 9.

Such a re-fill liquid enters into the accumulator battery followingdirection 313 passing through hole 37 of the transversal surface 36,until the level 561 of the electrolyte 61 reaches, as can be observed inFIG. 10, the level 560. In such a condition, the floating element 39 islifted upward so that the shutter 42 of the tubular stick 38 cansealingly close the hole 37 drilled in the transversal surface 36.

When hole 37 is closed, the liquid accumulated inside the build-upchamber 43 produces a pressure 270 against the flexible membrane 40which causes its deformation, as can be observed in FIG. 10.

Such a pressure, by acting against the surface of the membrane 40,produces a force 332 which follows the same direction as the directionof the force 331 caused by the pushing force of the floating body 39.Therefore, on the stick 38 and, consequently on the shutter 42 belongingto it, a total force 333 is achieved, which closes the through hole 37,said force being stronger than the single force 331 caused by thefloating force alone. Such an additional force 332 ensures a perfectclosing of the shutter 42, even in case the accumulator batteryundergoes vibrations during the re-filling operation. This eliminatesany eventual leakages, caused by possible oscillations which areencountered during the re-filling operation by using the re-fill devicesbelonging to the known technique, and said second device 30 ensures thesame sealing effects which are obtained by the automatic re-fill deviceobject of the patent application N. VI94A000139 in the name of the sameapplicant of the present patent.

It is pointed out that the liquid present inside the build-up chamber 43cannot go through the duct 50 and from here inside the accumulatorbattery through the vertical duct 62, since its passage is blocked bythe presence of the capillary section 56 connecting said ducts 50 and 5with one another.

In order to obtain the quick re-charge, through said second ducts 34,air following direction 634 is blown into the build-up chamber 43 which,as can be observed in FIG. 7, through duct 50 and the capillary section56, reaches channel 5 from which it then flows following direction 635into the vertical duct 62 present inside the container 6 and from herearrives near the bottom 71. The air 636 inside the electrolyte 61prevents the stratification of the electrolyte itself and facilitates,therefore, a quick re-charge.

During the re-filling and re-charging operations, the fumes producedflow out following direction 134 passing through the holes 234 drilledin the tubular stick 38 above the floating body 39, going along thetubular stick 38 and then flowing out through said first ducts 33, ascan be observed in the FIGS. 7, 8 and 9.

It is pointed out that each element of the accumulator battery can beequipped with a closing cap, in which case, in order to carry out there-charging operations, it is necessary to insert one of the describeddevices in each of the holes lodging one of said caps. If, on the otherhand, all the elements which form the accumulator battery are equippedwith a multiple closing device, only one of the described devices willbe used, this feeding all of the caps of the accumulator battery with asingle feeding line. On the basis of what has been described, it isunderstood that the present invention achieves all the proposedpurposes.

First of all, the lid and the first device which can be coupled with itforming the object of the present invention, permit to the manufacturerto obtain a quick charge for the formation of the elements, beforesending the accumulator battery to the user.

Also, by using the lid and the second device which can be coupled withit, forming the object of the present invention too, the purpose ofpermitting to the user to perform the quick charges of the accumulatorbattery and the refill of electrolyte, is also achieved.

Moreover, it has been seen that both said devices applied to said lidalso permit, during the quick re-charging operations, the conveyance andexhaust of the fumes which are produced during the re-charge. In thisway, it is possible to have a canalization which, by conveying the fumesaway from the area where the charge of the accumulator batteries occurs,permits to operate in a less polluted environment.

I claim:
 1. A lid for an accumulator battery for communicating with a circulating device for circulating electrolyte into and out of the accumulator, said accumulator being formed with an inner vertical wall and including an upper surface of said lid formed with at least one first hole and one second hole therein; at least one first device for the first hole having a cylindrical sidewall surface for circulation of electrolyte into and out of the accumulator during a first charge; and said at least one second device for the second hole for refilling electrolyte and for subsequent charges of the accumulator, said lid being including a plurality of channels in said upper surface, each channel having a first end and a second end, said first end facing the cylindrical surface of each of said first holes, and at least one duct located on the inner vertical wall of the container having a lower end terminating near the bottom of the container and an upper end coupled to the second end of the channel in said lid and being in registration therewith, said first device comprising a body having a cylindrical side wall formed with an annular recess; and sized so as to be sealably inserted into said first hole for communicating with the channels;a first pipe and a second pipe; said body having a first way and a second way, the first way for allowing electrolyte into the accumulator battery, the first way having a first end for receiving electrolyte from the circulating device and a second end for communicating with the annular recess and with the first end of the said channel, and way for allowing electrolyte to flow out of the accumulator battery, the second way having a first end for communicating with the circulating device for discharging electrolyte therefrom, and a second end locatable at a selected level within the container to maintain by overflow a level of electrolyte inside the accumulator battery, and wherein said second way comprises a tubular element slidably located in the chamber having an inner wall forming an annular area therebetween, said tubular element having a annular web for engaging the inner wall, said annular area having an upper area and a lower area separated from one another by said annular web, each having an opening to permit the inlet or the outlet of air under pressure, said openings for selectively permitting vertical displacement of said tubular element whenever said openings are fed by air under pressure acting against said annular web.
 2. A lid for an accumulator battery for communicating with a circulating device for circulating electrolyte into and out of the accumulator, said accumulator being formed with an inner vertical wall and including an upper surface of said lid formed with at least one first hole and one second hole therein; at least one first device for the first hole having a cylindrical sidewall surface for circulation of electrolyte into and out of the accumulator during a first charge; and said at least one second device for the second hole for refilling electrolyte and for subsequent charges of the accumulator, said lid including a plurality of channels in said upper surface, each channel having a first end and a second end, said first end facing the cylindrical surface of each of said first holes, and at least one duct located on the inner vertical wall of the container having a lower end terminating near the bottom of the container and an upper end coupled to the second end of the channel in said lid and being in registration therewith, said first device comprising a body having a cylindrical side wall formed with an annular recess; and sized so as to be sealably inserted into said first hole for communicating with the channels;a first pipe and a second pipe; said body having a first way and a second way, the first way for allowing electrolyte into the accumulator battery, the first way having a first end for receiving electrolyte from the circulating device and a second end for communicating with the annular recess and with the first end of the said channel, the second way for allowing electrolyte to flow out of the accumulator battery, and having a first end for communicating with the circulating device for discharging electrolyte therefrom, and a second end locatable at a selected level within the container to maintain by overflow a level of electrolyte inside the accumulator battery.
 3. A lid according to claim 2, wherein the first device includes an upstanding cylindrical chamber, and wherein said second way comprises a tubular element slidably located in the chamber having an inner wall forming an annular area therebetween, said tubular element having a annular web for engaging the inner wall, said annular area having an upper area and a lower area separated from one another by said annular web, each having an opening to permit the inlet or the outlet of air under pressure, said openings for selectively permitting vertical displacement of said tubular element whenever said openings are fed by air under pressure acting against said annular web.
 4. A lid according to claim 2 wherein said second device comprisesa body adapted to be sealingly coupled within said second hole and having a cavity with a bottom, said body having one or more first ducts for exhaustion of fumes and one or more second ducts for the inlet of the re-fill liquid; a tubular element having an outer tubular part extending within said cavity of said body and a cylindrical guiding element co-axial within said outer tubular part, said tubular element having a middle position, a transversal surface with a through hole and, laterally on the cylindrical wall, and one or more through openings communicating with at least one of said one or more second ducts; a tubular stick slidingly coupled within said through hole of said transversal surface and having, at one end, a floating body for co-operating with liquid in the accumulator battery and, at the opposite end, a flexible membrane connected with said tubular stick through first sealingly locking means and connected with the inner lateral surface of said tubular element through second sealingly locking means, said tubular stick including centrally located closing means to sealingly co-operate within said hole of said transversal surface so as to selectively allow and to prevent the passage of re-fill liquid flowing from said one or more second ducts, said flexible membrane defining a discharge chamber, inside one side of said cavity of said body, which communicates with said one or more first ducts and with the end of said tubular stick and, on the opposite side, a build-up chamber for the collection of re-fill liquid which communicates with said one or more second ducts and within which the pressure of said liquid therein, causes the deformation of said membrane, thereby producing on said tubular stick a force such as to increase pressure exerted by said floating body against said closing means, wherein said build-up chamber communicates with a duct equipped with a capillary section joining an annular recess on the outer surface of said body, said annular recess defining, together with the wall of the hole lodging said device, an annular chamber which communicates with said tubular channel of said lid, said capillary section preventing the passage of electrolyte from the build-up chamber to said channel but permitting the passage of compressed air which is let into said second inlet duct of said device during re-charging of the accumulator battery.
 5. A lid according to claim 4, wherein said pressure of said liquid contained inside said build-up chamber is such so as to exert on said membrane a force which is weaker than the total weight of said floating body and of said tubular stick supporting it.
 6. A lid according to claim 4, wherein said tubular stick supporting said floating body has one or more through holes for the exhaustion of fumes, said through holes being arranged above said floating body.
 7. A lid according to claim 4, wherein said tubular stick has external guiding fins slidingly coupling with the inner surface of a guiding element of said tubular element.
 8. A lid according to claim 4, wherein said one or more first ducts are located opposite to one another on the same horizontal plane and two of said second ducts are located opposite to one another on a horizontal plane which is parallel with the plane on which said first ducts lie.
 9. A lid (30) according to claim 4, wherein said closing means belonging to said tubular stick consist of a shutter in the shape of a truncated cone, suited to couple by interference within said through hole of said transversal surface.
 10. A lid according to claim 4, wherein said transversal surface has a truncated-cone shape converging toward the interior of the accumulator battery. 